And with that buildup, Boardwalk Empire executed one of the most surprising moves in recent TV history: killing off James “Jimmy” Darmody (Michael Pitt), the show’s second-biggest character after Enoch “Nucky” Thompson (Steve Buscemi).

Nucky shot and killed his former protégé after a season-long power struggle for control of the Atlantic City booze trade. The Oedipal-conflicted young war veteran was the victim of his own tragic decisions, including a bungled assassination attempt on Nucky. Though many fans will regret losing Pitt’s character, the move gave viewers an uncompromising finale that allows Nucky to embrace his gangster destiny.

Below, Boardwalk Empire showrunner and executive producer Terence Winter, who wrote tonight’s finale, talks to EW about why Jimmy had to go, how he broke the news to Pitt and gives some hints about his plans for season 3 — which include a time jump and the introduction of new brash young character. And at the end of the interview, there’s a link to our exclusive interview with Pitt.

ENTERTAINMENT WEEKLY:When did you first know that you were going to kill off Jimmy?

TERENCE WINTER: Probably at the very beginning of season 2. The idea was to try and push things to their absolute limit, even if it makes it difficult for yourself and your writing team. If you take things to their logical extreme with the situation we created, Jimmy has betrayed Nucky, he tried to have him killed. You want to be honest about the storytelling. In the pilot, Jimmy told Nucky: “You can’t be half a gangster anymore.” We wanted with the first two seasons to follow that trajectory, where he goes full season from being the guy who doesn’t want to get his hands dirty to actually pulling the trigger himself. And what’s the strongest version of that? To pull the trigger on the very guy who told him, “You can’t be half a gangster anymore.” It’s like, “Guess what? You’re right. I can’t. And here’s me now fully becoming a gangster.” Anything short of Nucky doing it himself wouldn’t feel real, it wouldn’t be real. And it would be a cheat for us to say, “We want to keep our beloved character Jimmy Darmody alive.”

One of the things I wanted to do by design in the finale is make the audience pissed off [at the start of the episode]. I wanted people to say [when it seemed like Nucky and Jimmy would reconcile], “Oh great, after all that, it’s all going to be forgotten and Jimmy is going to be back in Nucky’s good graces.” I wanted them to think right up to the very end that Nucky is going to forgive him and take him back. It was a really hard decision. You’re sort of blowing up your own show, in some ways. Now we’re back in the writers room trying to figure out where we go from here without Jimmy Darmody.

My only concern plot-wise was wondering whether Jimmy would really go so willingly to what he likely believes is his death.

We know with [the previous week’s episode] that he’s so emotionally damaged. I don’t think Jimmy ever expected to come back alive from World War I. I think he probably left for the war hoping he would die and was surprised he survived. He’s been a walking dead person ever since we’ve met him. He’s come back and gone through the motions of a person trying to make his way in the world, but ultimately becomes resigned to his fate. He gets manipulated into this run against Nucky, who was his mentor, and really the only father figure of any meaning that he has. The plot failed and he knows, as a good solider, he’s going to have to fall on his sword. He fully knows what he’s walking into at the end. He’s not armed. He says goodbye to his son. He basically gives Richard Harrow permission to not come with him. He knows he needs to be punished. The circumstances of his life have unraveled to the point where he’s willing to accept his fate. And psychologically Harrow is prepared to respect that as a soldier.

You touch on this in that last answer, but I still wanted to ask: Especially in light of what happens this week, why was it important to have the flashback that included the scene of Jimmy having sex with his mom?

We wanted to answer the questions: Why were Jimmy and Angela together in the first place? What is the basis of this weird relationship with his mother? What’s this strange hold she has on him? From the very first moment you see Jimmy and his mother together it’s really inappropriate — you think it’s a girlfriend, then you learn it’s his mother. We just wanted to pay that story off. It gives us so much insight into Jimmy’s psychology and how things got to this point.

I’m still haunted by his mom’s “I used to kiss his little winky” line from the season premiere.

Exactly.

On The Sopranos, you guys killed off plenty of key roles — you wrote the amazing “Long Term Parking” episode (where Adriana died). Arguably, this is a bigger move than any Sopranos hit. Do you have any concern about losing such a popular character?